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Cells Oct 2022The tumor suppressor PTEN mainly inhibits the PI3K/Akt pathway in the cytoplasm and maintains DNA stability in the nucleus. The status of PTEN remains therapeutic...
The tumor suppressor PTEN mainly inhibits the PI3K/Akt pathway in the cytoplasm and maintains DNA stability in the nucleus. The status of PTEN remains therapeutic effectiveness for chemoresistance of the DNA alkylating agent temozolomide (TMZ) in glioblastoma (GB). However, the underlying mechanisms of PTEN's interconnected role in the cytoplasm and nucleus in TMZ resistance are still unclear. In this study, we report that TMZ-induced PTEN nuclear import depends on PTEN ubiquitylation modification by Smurf1. The Smurf1 suppression decreases the TMZ-induced PTEN nuclear translocation and enhances the DNA damage. In addition, Smurf1 degrades cytoplasmic PTEN K289E (the nuclear-import-deficient PTEN mutant) to activate the PI3K/Akt pathway under TMZ treatment. Altogether, Smurf1 interconnectedly promotes PTEN nuclear function (DNA repair) and cytoplasmic function (activation of PI3K/Akt pathway) to resist TMZ. These results provide a proof-of-concept demonstration for a potential strategy to overcome the TMZ resistance in PTEN wild-type GB patients by targeting Smurf1.
Topics: Humans; Temozolomide; Glioblastoma; Proto-Oncogene Proteins c-akt; Phosphatidylinositol 3-Kinases; Cell Line, Tumor; Drug Resistance, Neoplasm; Alkylating Agents; PTEN Phosphohydrolase; Ubiquitin-Protein Ligases
PubMed: 36291166
DOI: 10.3390/cells11203302 -
Analytical Chemistry Dec 2015A high-resolution/accurate-mass DNA adductomic approach was developed to investigate anticipated and unknown DNA adducts induced by DNA alkylating agents in biological...
A high-resolution/accurate-mass DNA adductomic approach was developed to investigate anticipated and unknown DNA adducts induced by DNA alkylating agents in biological samples. Two new features were added to a previously developed approach to significantly broaden its scope, versatility, and selectivity. First, the neutral loss of a base (guanine, adenine, thymine, or cytosine) was added to the original methodology's neutral loss of the 2'-deoxyribose moiety to allow for the detection of all DNA base adducts. Second, targeted detection of anticipated DNA adducts based on the reactivity of the DNA alkylating agent was demonstrated by inclusion of an ion mass list for data dependent triggering of MS(2) fragmentation events and subsequent MS(3) fragmentation. Additionally, untargeted screening of the samples, based on triggering of an MS(2) fragmentation event for the most intense ions of the full scan, was included for detecting unknown DNA adducts. The approach was tested by screening for DNA mono and cross-linked adducts in purified DNA and in DNA extracted from cells treated with PR104A, an experimental DNA alkylating nitrogen mustard prodrug currently under investigation for the treatment of leukemia. The results revealed the ability of this new DNA adductomic approach to detect anticipated and unknown PR104A-induced mono and cross-linked DNA adducts in biological samples. This methodology is expected to be a powerful tool for screening for DNA adducts induced by endogenous or exogenous exposures.
Topics: Alkylating Agents; Alkylation; Chromatography, Liquid; Cross-Linking Reagents; DNA; Tandem Mass Spectrometry
PubMed: 26509677
DOI: 10.1021/acs.analchem.5b02759 -
Cells Oct 2023Sulfur mustard (SM) and its derivatives are potent genotoxic agents, which have been shown to trigger the activation of poly (ADP-ribose) polymerases (PARPs) and the...
Sulfur mustard (SM) and its derivatives are potent genotoxic agents, which have been shown to trigger the activation of poly (ADP-ribose) polymerases (PARPs) and the depletion of their substrate, nicotinamide adenine dinucleotide (NAD). NAD is an essential molecule involved in numerous cellular pathways, including genome integrity and DNA repair, and thus, NAD supplementation might be beneficial for mitigating mustard-induced (geno)toxicity. In this study, the role of NAD depletion and elevation in the genotoxic stress response to SM derivatives, i.e., the monofunctional agent 2-chloroethyl-ethyl sulfide (CEES) and the crosslinking agent mechlorethamine (HN2), was investigated with the use of NAD booster nicotinamide riboside (NR) and NAD synthesis inhibitor FK866. The effects were analyzed in immortalized human keratinocytes (HaCaT) or monocyte-like cell line THP-1. In HaCaT cells, NR supplementation, increased NAD levels, and elevated PAR response, however, did not affect ATP levels or DNA damage repair, nor did it attenuate long- and short-term cytotoxicities. On the other hand, the depletion of cellular NAD via FK866 sensitized HaCaT cells to genotoxic stress, particularly CEES exposure, whereas NR supplementation, by increasing cellular NAD levels, rescued the sensitizing FK866 effect. Intriguingly, in THP-1 cells, the NR-induced elevation of cellular NAD levels did attenuate toxicity of the mustard compounds, especially upon CEES exposure. Together, our results reveal that NAD is an important molecule in the pathomechanism of SM derivatives, exhibiting compound-specificity. Moreover, the cell line-dependent protective effects of NR are indicative of system-specificity of the application of this NAD booster.
Topics: Humans; Alkylating Agents; NAD; Protective Factors; Poly(ADP-ribose) Polymerases; DNA
PubMed: 37830610
DOI: 10.3390/cells12192396 -
Radiation Oncology (London, England) Jan 2022Radiotherapy (RT) is a mainstay of treatment for patients with glioblastoma (GB). Early clinical trials show that short course hypofractionation showed no survival... (Comparative Study)
Comparative Study
BACKGROUND
Radiotherapy (RT) is a mainstay of treatment for patients with glioblastoma (GB). Early clinical trials show that short course hypofractionation showed no survival benefit compared to conventional regimens with or without temozolomide chemotherapy (TMZ) but reduces the number of doses required. Concerns around delayed neurological deficits and reduced cognition from short course hypofractionated RT remain a concern. The aim of this study was to evaluate the effect of increased interfractional time using two different radiation fractionation regimens on GB.
METHODS
The radiobiological effect of increasing doses 0-20 Gy x-ray photon RT on Gl261 and CT2A GB cell lines was compared by colony forming assay, DNA damage by alkaline comet assay, oxidative stress, DNA damage, cell cycle, and caspase-3/7 by MUSE® flow cytometric analyses, and protein expression by western blot analyses. Conventional (20 Gy/10 fractions) and hypofractionated (20 Gy/4 fractions spaced 72 h apart) RT regimens with and without TMZ (200 mg/kg/day) were performed in syngeneic Gl261 and CT2A intracranial mouse models using the Small Animal Radiation Research Platform (Xstrahl Inc.).
RESULTS
X-ray photon radiation dose-dependently increased reactive oxygen species, DNA damage, autophagy, and caspase 3/7-mediated apoptotic cell death. While the conventional fractionated dose regimen of 20 Gy/10 f was effective at inducing cell death via the above mechanism, this was exceeded by a 20 Gy/4 f regimen which improved median survival and histopathology in Gl261-tumor bearing mice, and eradicated tumors in CT2A tumors with no additional toxicity.
CONCLUSIONS
Spacing of hypofractionated RT doses 72 h apart showed increased median survival and tumor control via increased activation of RT-mediated cell death, with no observed increased in radiotoxicity. This supports further exploration of differential RT fractionated regimens in GB clinical trials to reduce delayed neurological radiotoxicity.
Topics: Animals; Antineoplastic Agents, Alkylating; Glioblastoma; Mice; Radiation Dose Hypofractionation; Radiotherapy; Temozolomide; Time Factors; Treatment Outcome
PubMed: 35073960
DOI: 10.1186/s13014-022-01990-y -
Journal For Immunotherapy of Cancer May 2020Temozolomide (TMZ) chemotherapy is a current standard of care for glioblastoma (GBM), however it has only extended overall survival by a few months. Because it also...
BACKGROUND
Temozolomide (TMZ) chemotherapy is a current standard of care for glioblastoma (GBM), however it has only extended overall survival by a few months. Because it also modulates the immune system, both beneficially and negatively, understanding how TMZ interacts with immunotherapeutics is important. Oncolytic herpes simplex virus (oHSV) is a new class of cancer therapeutic with both cytotoxic and immunostimulatory activities. Here, we examine the combination of TMZ and an oHSV encoding murine interleukin 12, G47Δ-mIL12, in a mouse immunocompetent GBM model generated from non-immunogenic 005 GBM stem-like cells (GSCs.
METHODS
We first investigated the cytotoxic effects of TMZ and/or G47Δ-IL12 treatments in vitro, and then the antitumor effects of combination therapy in vivo in orthotopically implanted 005 GSC-derived brain tumors. To improve TMZ sensitivity, O-methylguanine DNA methyltransferase (MGMT) was inhibited. The effects of TMZ on immune cells were evaluated by flow cytometery and immunohistochemistry.
RESULTS
The combination of TMZ+G47Δ-IL12 kills 005 GSCs in vitro better than single treatments. However, TMZ does not improve the survival of orthotopic tumor-bearing mice treated with G47Δ-IL12, but rather can abrogate the beneficial effects of G47Δ-IL12 when the two are given concurrently. TMZ negatively affects intratumor T cells and macrophages and splenocytes. Addition of MGMT inhibitor O-benzylguanine (O6-BG), an inactivating pseudosubstrate of MGMT, to TMZ improved survival, but the combination with G47Δ-IL12 did not overcome the antagonistic effects of TMZ treatment on oHSV therapy.
CONCLUSIONS
These results illustrate that chemotherapy can adversely affect oHSV immunovirotherapy. As TMZ is the standard of care for GBM, the timing of these combined therapies should be taken into consideration when planning oHSV clinical trials with chemotherapy for GBM.
Topics: Animals; Antineoplastic Agents, Alkylating; Brain Neoplasms; Glioblastoma; Humans; Mice; Oncolytic Virotherapy; Temozolomide
PubMed: 32457126
DOI: 10.1136/jitc-2019-000345 -
Molecules (Basel, Switzerland) Aug 2014PM00104 (Zalypsis®) is a synthethic tetrahydroisoquinolone alkaloid, which is structurally similar to many marine organisms. The compound has been proposed as a... (Review)
Review
PM00104 (Zalypsis®) is a synthethic tetrahydroisoquinolone alkaloid, which is structurally similar to many marine organisms. The compound has been proposed as a potential chemotherapeutic agent in the treatment of solid human tumors and hematological malignancies. PM00104 is a DNA binding agent, causing inhibition of the cell cycle and transcription, which can lead to double stranded DNA breaks. After rigorous pre-clinical testing, the drug has been evaluated in a number of phase II clinical trials. This manuscript provides a review of current trials and appraises the efficacy of PM00104 as a future cancer treatment.
Topics: Antineoplastic Agents, Alkylating; Aquatic Organisms; Clinical Trials as Topic; Drug Screening Assays, Antitumor; Humans; Neoplasms; Tetrahydroisoquinolines
PubMed: 25153860
DOI: 10.3390/molecules190812328 -
Neuro-oncology Apr 2023The goal was to determine whether the addition of temozolomide (TMZ) to the standard treatment of high-dose methotrexate (HD-MTX) and whole-brain radiotherapy (WBRT) for... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The goal was to determine whether the addition of temozolomide (TMZ) to the standard treatment of high-dose methotrexate (HD-MTX) and whole-brain radiotherapy (WBRT) for primary central nervous system lymphoma (PCNSL) improves survival.
METHODS
An open-label, randomized, phase III trial was conducted in Japan, enrolling immunocompetent patients aged 20-70 years with histologically confirmed, newly diagnosed PCNSL. After administration of HD-MTX, patients were randomly assigned to receive WBRT (30 Gy) ± 10 Gy boost (arm A) or WBRT ± boost with concomitant and maintenance TMZ for 2 years (arm B). The primary endpoint was overall survival (OS).
RESULTS
Between September 29, 2014 and October 15, 2018, 134 patients were enrolled, of whom 122 were randomly assigned and analyzed. At the planned interim analysis, 2-year OS was 86.8% (95% confidence interval [CI]: 72.5-94.0%) in arm A and 71.4% (56.0-82.2%) in arm B. The hazard ratio was 2.18 (95% CI: 0.95-4.98), with the predicted probability of showing the superiority of arm B at the final analysis estimated to be 1.3%. The study was terminated early due to futility. O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status was measured in 115 tumors, and it was neither prognostic nor predictive of TMZ response.
CONCLUSIONS
This study failed to demonstrate the benefit of concomitant and maintenance TMZ in newly diagnosed PCNSL.
Topics: Humans; Temozolomide; Methotrexate; Disease-Free Survival; Lymphoma; Brain; Central Nervous System Neoplasms; Antineoplastic Agents, Alkylating
PubMed: 36334050
DOI: 10.1093/neuonc/noac246 -
Redox Biology May 2022Overproduction of reactive oxygen species (ROS) drives inflammation and mutagenesis. However, the role of the DNA damage response in immune responses remains largely...
Overproduction of reactive oxygen species (ROS) drives inflammation and mutagenesis. However, the role of the DNA damage response in immune responses remains largely unknown. Here we found that stabilization of the mismatch repair (MMR) protein MSH6 in response to alkylation damage requires interactions with the molybdopterin synthase associating complex (MPTAC) and Ada2a-containing histone acetyltransferase complex (ATAC). Furthermore, MSH6 promotes sterol biosynthesis via the mevalonate pathway in a MPTAC- and ATAC-dependent manner. MPTAC reduces the source of alkylating agents (ROS). Therefore, the association between MMR proteins, MPTAC, and ATAC promotes anti-inflammation response and reduces alkylating agents. The inflammatory responses measured by xanthine oxidase activity are elevated in Lymphoblastoid Cell Lines (LCLs) from some Fragile X-associated disorders (FXD) patients, suggesting that alkylating agents are increased in these FXD patients. However, MPTAC is disrupted in LCLs from some FXD patients. In LCLs from other FXD patients, interaction between MSH6 and ATAC was lost, destabilizing MSH6. Thus, impairment of MPTAC and ATAC may cause alkylation damage resistance in some FXD patients.
Topics: Alkylating Agents; Alkylation; DNA Damage; DNA Repair; DNA-Binding Proteins; Humans; Reactive Oxygen Species; Sterols
PubMed: 35189552
DOI: 10.1016/j.redox.2022.102270 -
Cells Apr 2022Glioblastoma is a highly aggressive, invasive and treatment-resistant tumour. The DNA damage response (DDR) provides tumour cells with enhanced ability to activate cell...
Glioblastoma is a highly aggressive, invasive and treatment-resistant tumour. The DNA damage response (DDR) provides tumour cells with enhanced ability to activate cell cycle arrest and repair treatment-induced DNA damage. We studied the expression of DDR, its relationship with standard treatment response and patient survival, and its activation after treatment. The transcriptomic profile of DDR pathways was characterised within a cohort of isocitrate dehydrogenase (IDH) wild-type glioblastoma from The Cancer Genome Atlas (TCGA) and 12 patient-derived glioblastoma cell lines. The relationship between DDR expression and patient survival and cell line response to temozolomide (TMZ) or radiation therapy (RT) was assessed. Finally, the expression of 84 DDR genes was examined in glioblastoma cells treated with TMZ and/or RT. Although distinct DDR cluster groups were apparent in the TCGA cohort and cell lines, no significant differences in OS and treatment response were observed. At the gene level, the high expression of , and independently associated with poor prognosis in glioblastoma patients. Finally, we observed a substantial upregulation of DDR genes after treatment with TMZ and/or RT, particularly in RT-treated glioblastoma cells, peaking within 24 h after treatment. Our results confirm the potential influence of DDR genes in patient outcome. The observation of DDR genes in response to TMZ and RT gives insight into the global response of DDR pathways after adjuvant treatment in glioblastoma, which may have utility in determining DDR targets for inhibition.
Topics: Antineoplastic Agents, Alkylating; DNA Damage; Glioblastoma; Humans; Temozolomide; Transcriptome
PubMed: 35406779
DOI: 10.3390/cells11071215 -
Nucleic Acids Research May 2018Exposure to many endogenous and exogenous agents can give rise to DNA alkylation, which constitutes a major type of DNA damage. Among the DNA alkylation products, alkyl...
Exposure to many endogenous and exogenous agents can give rise to DNA alkylation, which constitutes a major type of DNA damage. Among the DNA alkylation products, alkyl phosphotriesters have relatively high frequencies of occurrence and are resistant to repair in mammalian tissues. However, little is known about how these lesions affect the efficiency and fidelity of DNA replication in cells or how the replicative bypass of these lesions is modulated by translesion synthesis DNA polymerases. In this study, we synthesized oligodeoxyribonucleotides containing four pairs (Sp and Rp) of alkyl phosphotriester lesions at a defined site, and examined how these lesions are recognized by DNA replication machinery in Escherichia coli cells. We found that the Sp diastereomer of the alkyl phosphotriester lesions could be efficiently bypassed, whereas the Rp counterparts moderately blocked DNA replication. Moreover, the Sp-methyl phosphotriester induced TT→GT and TT→GC mutations at the flanking TT dinucleotide site, and the induction of these mutations required Ada protein, which is known to remove efficiently the methyl group from the Sp-methyl phosphotriester. Together, our study provided a comprehensive understanding about the recognition of alkyl phosphotriester lesions by DNA replication machinery in cells, and revealed for the first time the Ada-dependent induction of mutations at the Sp-methyl phosphotriester site.
Topics: Alkylation; DNA Damage; DNA Repair; DNA Replication; DNA, Bacterial; DNA-Directed DNA Polymerase; Escherichia coli; Escherichia coli Proteins; Mutagenesis; Mutation; O(6)-Methylguanine-DNA Methyltransferase; Stereoisomerism; Transcription Factors
PubMed: 29514270
DOI: 10.1093/nar/gky140